Organic light-emitting display apparatus

ABSTRACT

In an aspect, an organic light-emitting display apparatus is provided, including: an insulating layer having a inclined structure; a first electrode disposed on the insulating layer; a selective wavelength transparent layer disposed on the first electrode; a pixel defined layer disposed on the insulating layer and the first electrode and defining an emissive region and a non-emissive region; an organic emissive layer disposed on the first electrode; and a second electrode disposed on the organic emissive layer.

INCORPORATION BY REFERENCE TO RELATED APPLICATIONS

Any and all priority claims identified in the Application Data Sheet, orany correction thereto, are hereby incorporated by reference under 37CFR 1.57. For example, this application claims priority to and thebenefit of Korean Patent Application No. 10-2013-0022451, filed on Feb.28, 2013, in the Korean Intellectual Property Office, the disclosure ofwhich is incorporated herein in its entirety by reference.

BACKGROUND

1. Field

This disclosure relates to an organic light-emitting display apparatus,and more particularly, to an organic light-emitting display apparatushaving excellent light efficiency and that is capable of reducingreflectivity of external light.

2. Description of the Related Technology

Generally, an organic light-emitting display apparatus is aself-emission display which is formed by using an organic light-emittingdiode (OLED) which includes a hole-injecting electrode, anelectron-injecting electrode, and an organic light-emitting layer formedtherebetween. The organic light-emitting display apparatus emits lightwhen an exciton, generated when a hole injected from the hole-injectingelectrode and an electron injected from the electron-injecting electrodeare combined, drops from an excitation state to a ground state.

Since the organic light-emitting display apparatus, which is aself-emission display, does not need an additional power source, it maybe driven with a low voltage, and may be formed of light films.Additionally, the organic light-emitting display apparatus provideshigh-quality characteristics such as wide viewing angles, high contrast,and a rapid response. Thus, an organic light-emitting display apparatusreceives consideration as a next-generation display apparatus.

SUMMARY

The present disclosure provides an organic light-emitting displayapparatus having excellent light efficiency and that is capable ofreducing reflectivity of external light.

According to an aspect of the present disclosure, there is provided anorganic light-emitting display apparatus including: an insulating layerhaving a inclined structure; a first electrode disposed on theinsulating layer; a selective wavelength transparent layer disposed onthe first electrode; a pixel defined layer disposed on the insulatinglayer and the first electrode and defining an emissive region and anon-emissive region; an organic emissive layer disposed on the firstelectrode; and a second electrode disposed on the organic emissivelayer.

In some embodiments, the first electrode may be provided on a bottomsurface and a sidewall of the inclined structure.

In some embodiments, the pixel defined layer may extend on an uppersurface of the insulating layer, and the emissive region may include anopening exposing the first electrode.

In some embodiments, the pixel defined layer may cover the selectivewavelength transparent layer.

In some embodiments, an N(N°3, N is an integer) number of low refractiveindex layers and an N number of high refractive index layers may bealternately stacked in the selective wavelength transparent layer.

In some embodiments, a difference in a refractive index between the Nnumber of low refractive index layers and the N number of highrefractive index layers may be equal to or greater than 0.5.

In some embodiments, a thickness of one of the N number of lowrefractive index layers may be greater than thicknesses of the other lowrefractive index layers. In some embodiments, one of the low refractiveindex layers has a thickness T¹ and each of the other low refractiveindex layers has a thickness T². In some embodiments, the thickness T¹is greater than the thicknesses T².

In some embodiments, a thickness of an intermediate layer of the lowrefractive index layers may be greater than thicknesses of the other lowrefractive index layers.

In some embodiments, a sidewall of the inclined structure may have atilt angle in a range from about 20 degrees to about 70 degrees withrespect to an extending line of a bottom surface of the inclinedstructure.

In some embodiments, the inclined structure may have a recess shape, andthe first electrode may have a concave shape.

In some embodiments, the first electrode may be disposed on a sidewallof the inclined structure, and reflect light generated in the organicemissive layer.

In some embodiments, the inclined structure may have a protruding shape,and the first electrode may have a convex shape.

In some embodiments, the first electrode may be a transparent electrode,and the second electrode may be a bottom emissive type including areflective layer.

According to another aspect of the present disclosure, there is providedan organic light-emitting display apparatus including: a substrate; aninsulating layer disposed on the substrate and including a recess havinga inclined surface; an organic light-emitting diode (OLED) disposed onthe insulating layer and including a first electrode, an organicemissive layer, and a second electrode; a pixel defined layer disposedbetween the first electrode and the second electrode and defining anemissive region and a non-emissive region; and a selective wavelengthtransparent layer provided on the inclined surface.

In some embodiments, the first electrode may be disposed on the inclinedsurface.

In some embodiments, the insulating layer may further comprise aplurality of recesses, and the OLED may be disposed in each of therecesses.

In some embodiments, an N(N≧3, N is an integer) number of low refractiveindex layers and an N number of high refractive index layers may bealternately stacked in the selective wavelength transparent layer,wherein a thickness of one of the N number of low refractive indexlayers is different from thicknesses of the other low refractive indexlayers. In some embodiments, one of the low refractive index layers hasa thickness T³ and each of the other low refractive index layers has athickness T⁴, and wherein thickness T³ is different than the thicknessesT⁴.

In some embodiments, the organic light-emitting display apparatus mayfurther include: a thin film transistor connected to the firstelectrode.

In some embodiments, the organic light-emitting display apparatus mayfurther include: a sealing film covering the OLED.

In some embodiments, the first electrode may include a reflective layer.

According to another aspect of the present disclosure, there is providedan organic light-emitting display apparatus including: a substrate; aninsulating layer disposed on the substrate and including a plurality ofrecesses each having a inclined surface; a plurality of OLEDs disposedon the insulating layer and including a first electrode, an organicemissive layer, and a second electrode; and a pixel defined layerdisposed between the first electrode and the second electrode anddefining an emissive region and a non-emissive region, wherein the pixeldefined layer is a color filter.

In some embodiments, the inclined surface may have a tilt angle in arange from about 20 degrees to about 70 degrees with respect to aparallel line of the substrate.

In some embodiments, the first electrode may be disposed on the inclinedsurface.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present disclosurewill become more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings in which:

FIG. 1 is a cross-sectional view of an organic light-emitting displayapparatus according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of an organic light-emitting displayapparatus according to another embodiment of the present invention;

FIG. 3 is a schematic cross-sectional view of a region I of FIGS. 1 and2;

FIGS. 4 and 5 are schematic cross-sectional views of a selectivewavelength transparent layer applied to embodiments of the presentinvention;

FIGS. 6A through 6C are graphs showing a characteristic of the selectivewavelength transparent layer of FIG. 5 according to a design changethereof;

FIG. 7 is a schematic cross-sectional view of a region I of FIGS. 1 and2, according to another embodiment of the present invention; and

FIG. 8 is a schematic cross-sectional view of a region I of FIGS. 1 and2, according to another embodiment of the present invention.

DETAILED DESCRIPTION

The present disclosure will now be described more fully with referenceto the accompanying drawings, in which exemplary embodiments are shownLike reference numerals in the drawings denote like elements, and thustheir description will be omitted. In the drawings, the lengths andsizes of elements are exaggerated for clarity and convenience ofdescription.

This disclosure may be embodied in many different forms and should notbe construed as limited to the exemplary embodiments set forth herein.For example, it will be understood that when a layer is referred to asbeing “on” or “on the top of” another layer, the layer can be directlyon another layer or intervening or layers.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises,”“comprising,” “includes,” and/or “including,” when used herein, specifythe presence of stated steps, operations, and/or elements, but do notpreclude the presence or addition of one or more other steps,operations, and/or elements. It will be understood that, although theterms, ‘first’, ‘second’, etc. may be used herein to describe variouselements, these elements should not be limited by these terms. Theseterms are only used to distinguish one element from another.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items. Expressions such as “atleast one of,” when preceding a list of elements, modify the entire listof elements and do not modify the individual elements of the list.

FIGS. 1 and 2 are cross-sectional views of organic light-emittingdisplay apparatuses 1 and 2, according to embodiments of the presentinvention.

Referring to FIG. 1, the organic light-emitting display apparatus 1includes an organic emissive portion 22 provided on a substrate 21 and asealing substrate 23 that seals the organic emissive portion 22.

In some embodiments, the organic emissive portion 22 may include aplurality of organic light-emitting diodes (OLEDs) that emit one of red,green, blue, and white colors, as described later.

In some embodiments, the sealing substrate 23 may be formed of atransparent material to form an image from the organic emissive portion22 and to prevent oxygen and moisture from reaching the organic emissiveportion 22.

Edges of the substrate 21 and the sealing substrate 23 are coupled toeach other by using a sealing member 24 so that an inner space 25between the substrate 21 and the sealing substrate 23 is sealed. In someembodiments, a moisture absorbent or a filler may be disposed in theinner space 25.

Referring to FIG. 2, the organic light-emitting display apparatus 2includes the organic emissive portion 22 provided on the substrate 21and a sealing film 26 that seals the organic emissive portion 22.

The organic light-emitting display apparatus 2 of FIG. 2 is differentfrom the organic light-emitting display apparatus 1 of FIG. 1 in thatthe organic light-emitting display apparatus 2 includes the sealing film26 that is a thin film instead of the sealing substrate 23 of FIG. 1. Insome embodiments, the sealing film 26 may cover the organic emissiveportion 22 to protect the organic emissive portion 22 from external air.For example, the sealing film 26 may have a structure in which aninorganic layer formed of an inorganic substance such as silicon oxideor silicon nitride and an organic layer formed of an organic substancesuch as epoxy or polyimide are alternately formed.

In some embodiments, the number of inorganic layers or organic layersmay be plural.

In some embodiments, the organic layer may be formed of polymer, and bea single layer or multi-layer formed of one selected from the groupconsisting of polyethylene terephthalate, polyimide, polycarbonate,epoxy, polyethylene, and polyacrylate. In some embodiments, the organiclayer may also be formed of polyacrylate, and, more particularly,include a high molecular monomer component including a diacrylate-basedmonomer and a triacrylate-based monomer. In some embodiments, themonomer component may further include a monoacrylate-based monomer. Insome embodiments, the monomer component may further include a well-knownphotoinitiator such as TPO(2,4,6-Trimethylbenzoyl-diphenyl-phosphineoxide) but it is not limitedthereto.

In some embodiments, the inorganic layer may be a single layer ormulti-layer including metal oxide or metal nitride. In some embodiments,the inorganic layer may include one selected from the group consistingof SiNx, Al₂O₃, SiO₂, TiO₂, etc.

In some embodiments, an uppermost layer of the sealing film 26 that isexposed to the outside may be an inorganic layer so as to preventmoisture from reaching an OLED.

In some embodiments, the sealing film 26 may include at least onesandwich structure in which at least one organic layer is disposedbetween at least two inorganic layers. In some embodiments, the sealingfilm 26 may include at least one sandwich structure in which at leastone inorganic layer is disposed between at least two organic layers.

In some embodiments, the sealing film 26 may sequentially include afirst inorganic layer, a first organic layer, and a second inorganiclayer from an upper portion of the organic emissive portion 22. In someembodiments, the sealing film 26 may also include the first inorganiclayer, the first organic layer, the second inorganic layer, a secondorganic layer, and a third inorganic layer from the upper portion of theorganic emissive portion 22. In some embodiments, the sealing film 26may also include the first inorganic layer, the first organic layer, thesecond inorganic layer, the second organic layer, the third inorganiclayer, a third organic layer, and a fourth inorganic layer from theupper portion of the organic emissive portion 22.

In some embodiments, a halogenized metal layer including LiF may befurther disposed between the organic emissive layer 22 and the firstinorganic layer. In some embodiments, the halogenized metal layer mayprevent the organic emissive layer 22 from being damaged when the firstinorganic layer is formed using a sputtering method or plasma depositionmethod.

In some embodiments, the first organic layer may have a narrower areathan that of the second inorganic layer. In some embodiments, the secondorganic layer may also have a narrower area than that of the thirdinorganic layer. In some embodiments, the first organic layer may beentirely covered by the second inorganic layer. In some embodiments, thesecond organic layer may also be entirely covered by the third inorganiclayer.

As another example, the sealing film 26 may have a film structureincluding low melting glass such as tin oxide (SnO). However, this ismerely exemplary and the sealing film 26 is not necessarily limitedthereto.

FIG. 3 is a schematic cross-sectional view of region I of FIGS. 1 and 2.

Referring to FIG. 3, an organic light-emitting display apparatus 100 mayinclude the substrate 21, a buffer film 211, a thin film transistor TR,an insulating layer 210 including an inclined structure 209, an OLED, apixel defined layer 223, and a selective wavelength transparent layer30.

In some embodiments, the substrate 21 may be formed of transparent glasshaving silicon dioxide (SiO₂) as a main component. However, thesubstrate 21 is not necessarily limited thereto, and may be formed ofvarious materials such as ceramic, transparent plastic, metal, and thelike.

In some embodiments, the buffer film 211 may function to preventimpurity ions, moisture, or external air from reaching an upper surfaceof the substrate 21 and planarize a surface of the substrate 21. In someembodiments, the buffer film 211 may be formed of an inorganic substancesuch as silicon oxide, silicon nitride, silicon oxynitride, aluminumoxide, aluminum nitride, titanium oxide, or titanium nitride, etc., anorganic substance such as polyimide, polyester, acryl, etc., or a stackstructure of the inorganic substance and the organic substance. Thebuffer film 211 is not an indispensable element and may not be providedaccording to circumstances. In some embodiments, the buffer film 211 maybe formed by using diverse deposition methods such as plasma-enhancedchemical vapor deposition (PECVD), atmospheric pressure chemical vapordeposition (APCVD), low pressure CVD (LPCVD), and the like.

The thin film transistor TR includes an active layer 212, a gateelectrode 214, and source and drain electrodes 216 and 217. A gateinsulating layer 213 for insulating the gate electrode 214 from theactive layer 212 is disposed between the gate electrode 214 and theactive layer 212.

In some embodiments, the active layer 212 may be provided on the bufferfilm 211. In some embodiments, the active layer 212 may use an inorganicsemiconductor or an organic semiconductor such as amorphous silicon orpolysilicon. In some embodiments, the active layer 212 may be formed ofan oxide semiconductor. For example, the oxide semiconductor may includean oxide of at least one material selected from metal elements in Groups12 through 14 consisting of zinc (Zn), indium (In), gallium (Ga),stannum (Sn), cadmium (Cd), germanium (Ge), and hafnium (Hf), and acombination thereof.

In some embodiments, the gate insulating layer 213 may be provided onthe buffer film 211 to cover the active layer 212. In some embodiments,the gate electrode 214 may be formed on the gate insulating layer 213.

In some embodiments, an interlayer insulating layer 215 may be formed onthe gate insulating layer 213 to cover the gate electrode 214. In someembodiments, the source and drain electrodes 216 and 217 may be formedon the interlayer insulating layer 215 to contact the active layer 212through contact holes.

The above-described structure of the thin film transistor TR is notnecessarily limited thereto, and other structures of a thin filmtransistor TR may be applied. For example, the thin film transistor TRis formed as a top gate structure or may be formed as a bottom gatestructure in which the gate electrode 214 is disposed below the activelayer 212.

In some embodiments, a pixel circuit (not shown) including a capacitorand the thin film transistor TR may be formed.

In some embodiments, the insulating layer 210 may include the inclinedstructure 209. In some embodiments, the insulating layer 210 may beprovided on the interlayer insulating layer 215 to cover the pixelcircuit including the thin film transistor TR. In some embodiments, theinsulating layer 210 may be composed of a plurality of insulating films.

In some embodiments, the inclined structure 209 includes a planarizedbottom surface and a side wall having a tilt angle θ. In someembodiments, the inclined structure 209 may be provided to form a recesshaving inclined surface in a part of the insulating layer 210. The tiltangle θ refers to an angle formed by an extending line of a bottomsurface and a side wall of the inclined structure 209 and may beadjusted through a process. An upper width of the inclined structure 209may be greater than a lower width thereof since it has the side wallhaving the tilt angle θ. In some embodiments, the tilt angle θ may be ina range from about 20 degrees to about 70 degrees with respect to theextending line of the bottom surface.

In some embodiments, the insulating layer 210 may be formed of aninorganic substance and/or an organic substance. For example, theinsulating layer 210 may include photoresist, acryl-based polymer,polyimide-based polymer, polyamide-based polymer, siloxane-basedpolymer, polymer including a photosensitive acryl carboxyl group,novolac resin, alkali soluble resin, silicon oxide, silicon nitride,silicon oxynitride, silicon oxycarbide, silicon carbonitride, aluminum,magnesium, zinc, hafnium, zirconium, titanium, tantalum, aluminum oxide,titanium oxide, tantalum oxide, magnesium oxide, zinc oxide, hafniumoxide, zirconium oxide, etc.

In some embodiments, the insulating layer 210 may include a firstinsulating layer 218 and a second insulating layer 219. In someembodiments, the first insulating layer 218 may be a single-layered ormulti-layered insulating film having a planarized top surface. In someembodiments, the second insulating film 219 may be disposed on the firstinsulating layer 218 and have the inclined structure 209. In someembodiments, the first insulating layer 218 and the second insulatinglayer 219 may be formed of a same or similar material. In someembodiments, the first insulating layer 218 and the second insulatinglayer 219 may be also formed of different materials.

In some embodiments, the OLED may be disposed on the insulating layer210 and may include a first electrode 221, an organic emissive layer220, and a second electrode 222. In some embodiments, the pixel definedlayer 223 may be disposed on the insulating layer 210 and the firstelectrode 221 and defines an emissive region and a non-emissive region.

In some embodiments, the organic emissive layer 220 may be formed of alow-molecular weight organic material or a polymer organic material.When the organic emissive layer 220 is formed of a low-molecular weightorganic material, a hole injection layer (HIL), a hole transport layer(HTL), an emission layer (EML), an electron transport layer (ETL), anelectron injection layer (EIL), etc. may be stacked to form a single ormultiple structure. These low-molecular weight organic materials may beformed using a vacuum deposition method. In this regard, the organicemissive layer 220 may be independently formed for each of red R, greenG, and blue B pixels. The HIL, the HTL, the ETL, and the EIL may beapplied to the RGB pixels as common layers.

Otherwise, when the organic emissive layer 220 is formed of a polymerorganic material, only an HIL may be included with respect to an EML ina direction of the first electrode 221. In some embodiments, the HIL maybe formed of poly(3,4-ethylenedioxythiophene)(PEDOT) or polyaniline(PANI) and formed on an upper portion of the first electrode 221 usingan inkjet printing method or a spin coating method. In this regard, apolyphenylene vinylene (PPV) or polyfluorene-based polymer organicsubstance may be used as an organic material, and a color pattern may beformed using a general method such as the inkjet printing method or thespin coating method or a thermal transfer method using laser.

In some embodiments, the HIL may be formed of a phthalocyanine componentsuch as copper phthalocyanine or TCTA, m-MTDATA, m-MTDAPB, etc. that arestarburst type amine derivatives.

In some embodiments, the HTL may be formed ofN,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1-biphenyl]-4,4′-diamine(TPD), N,N′-di(naphthalene-1-yl),N′-diphenyl benzidine (α-NPD), etc.

In some embodiments, the EIL may be formed of LiF, NaCl, CsF, Li20, BaO,Liq, etc.

In some embodiments, the ETL may be formed of Alq₃.

In some embodiments, the EML may be formed of a host material and adopant material.

In some embodiments, the host material may use Tris(8-hydroxyquilonato)aluminum (Alq3), 9,10-di (naphth-2-yl)anthracene (AND),3-tert-butyl-9,10-di(naphth-2y1)anthracene (TBADN),4,4′-bis(2,2-diphenyl-ethene-1-yl)-4,4′-dimethylphenyl (DPVBi),4,4′-bis(2,2-diphenyl-ethene-1-yl)-4,4′-dimethylphenyl (p-DMDPVBi), Tert(9,9-diaryl-fluorene)-s (TDAF),2-(9,9′-spirobifluorene-2-yl)-9,9′-spirobifluorene (BSDF),2,7-bis(9,9′-spirobifluorene-2-yl)-9,9′-spirobifluorene (TSDF),bis-(9,9-diaryl-fluorene)s (BDAF),4,4′-bis(2,2-diphenyl-ethene-1-yl)-4,4′-di-(tert-butyl)phenyl(p-TDPVBi), 1,3-bis(carbazole-9-yl)benzene (mCP), 1,3,5-tris(carbazole-9-yl)benzene (tCP),4,4′,4″-tris(carbazole-9-yl)triphenylamine (TcTa),4,4′-bis(carbazole-9-yl)biphenyl (CBP),4,4′-bis(9-carbazolyl)-2,2′-dimethyl-biphenyl (CBDP),4,4′-bis(carbazole-9-yl)-9,9-dimethyl-fluorene (DMFL-CBP),4,4′-bis(carbazole-9-yl)-9,9-bis(9-phenyl-9H-carbazole)fluorene(FL-4CBP), 4,4′-bis(carbazole-9-yl)-9,9-di-tolyl-fluorene (DPFL-CBP),9,9-bis(9-phenyl-9H-carbazole)fluorene (FL-2CBP), etc.

In some embodiments, the dopant material may use4,4′bis[4-(di-p-tolylamino)styryl]biphenyl (DPAVBi),9,10-di(naph-2-thyl)anthracene (AND),3-tert-butyl-9,10-di(naph2-thyl)anthracene (TBADN), etc.

In some embodiments, the first electrode 221 may be disposed on theinsulating layer 210. In some embodiments, the first electrode 221 maybe disposed on the side wall of the inclined structure 209 with respectto the bottom surface thereof. In some embodiments, the first electrode221 may be at an angle that is the same as or similar to the tilt angleθ formed by the side wall of the inclined structure 209 with respect tothe extending line of the bottom surface of the inclined structure 209.In some embodiments, the first electrode 221 may have a concave shapesince it is disposed on the side wall of the inclined structure 209.

In a case where light generated in the organic emissive layer 220 isincident to the first electrode 221 disposed on the side wall of theinclined structure 209, the incident light may be reflected from thefirst electrode 221 and discharged to the outside. In this regard, thetilt angle θ may be adjusted in such a way that the light generated inthe organic emissive layer 220 may be emitted in a desired direction.Accordingly, an efficiency of the light discharged from the OLEDdisposed on the inclined structure 209 to the outside may be improved.

In some embodiments, the first electrode 221 may be electricallyconnected to the drain electrode 217 of the thin film transistor TR viaa through hole 208 that passes through the insulating layer 210.Although the through hole 208 is formed in the bottom surface of theinclined structure 209 in FIG. 3, the present embodiments are notlimited thereto. In some embodiments, the through hole 208 may be formedin the side wall of the inclined structure 209 or in an upper surface ofthe insulating layer 210.

In some embodiments, the first electrode 221 may function as an anodeand the second electrode 222 may function as a cathode. However, thepolarities of the first and second electrodes 221 and 222 are notlimited thereto and may be switched.

If the first electrode 221 functions as an anode, the first electrode221 may include indium tin oxide (ITO), indium zinc oxide (IZO), zincoxide (ZnO), or indium oxide (In₂O₃) having a high work function. If theorganic light-emitting display device 1 is a top emission type fordisplaying an image in a direction opposite to the display substrate 21,the first electrode 221 may further include a reflective layer includingmetal such as silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt),palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir),chromium (Cr), lithium (Li), ytterbium (Yb), or calcium (Ca), or analloy thereof. In some embodiments, the first electrode 221 may beformed as a monolayer or a multilayer including the above-mentionedmetal or alloy. In some embodiments, the first electrode 221 may includean ITO/Ag/ITO structure as a reflective electrode.

If the second electrode 222 functions as a cathode electrode, the secondelectrode 222 may be formed of metal such as Ag, Mg, Al, Pt, Pd, Au, Ni,Nd, Ir, Cr, Li, or Ca. If the organic light-emitting display device 1 isa top emission type, the second electrode 222 should transmit light. Insome embodiments, the second electrode 222 may include transparentconductive metal oxide such as ITO, IZO, zinc tin oxide (ZTO), ZnO, orIn₂O₃. According to another embodiment, the second electrode 222 may beformed as a thin film including at least one selected from the groupconsisting of Li, Ca, LiF/Ca, LiF/A1, Al, Ag, Mg, and Yb. For example,the second electrode 222 may be formed as a monolayer or a multilayerincluding Mg:Ag, Ag:Yb, and/or Ag. Unlike the first electrode 221, thesecond electrode 222 may be formed to apply a common voltage to allpixels.

In some embodiments, the pixel defining layer 219 defines the pixelregions PA of the OLEDs and the non-pixel region NPA by using aplurality of openings for exposing the first electrode 221. In theopening of the pixel defining layer 219, the first electrode 221, theorganic emission layer 220B or 220R, and the second electrode 222 may besequentially stacked and the organic emission layer 220B or 220R mayemit light. That is, a region where the pixel defining layer 219 isformed substantially corresponds to the non-pixel region NPA, and theopenings of the pixel defining layer 219 substantially correspond to thepixel regions PA.

In some embodiments, the pixel defined layer 223 may be disposed on theinsulating layer 210 and the first electrode 221 and may define theemissive region and the non-emissive region. In some embodiments, thepixel defined layer 223 may cover the first electrode 221 disposed onthe side wall of the inclined structure 209 and extend on the uppersurface of the insulating layer 210. In other words, the pixel definedlayer 223 may be disposed between a part of the bottom surface and anupper part of the side wall of the inclined structure 209. A part of thepixel defined layer 223 is the non-emissive region. In some embodiments,an opening (not shown) pixel defined layer disposed between the pixeldefined layers 223 and exposes the first electrode 221 may be theemissive region.

In some embodiments, the organic emissive layer 220 may be disposed onthe pixel defined layer 223. In other words, the organic emissive layer220 may be disposed on the first electrode 221 of the opening 223 a andextend on the upper portion of the pixel defined layer 223.

In some embodiments, the pixel defined layer 223 may be formed of anorganic material, an inorganic material, etc. For example, the pixeldefined layer 223 may include an organic material such as photoresist,polyacryl-based resin, polyimide-based resin, acryl-based polymer, or aninorganic material such as a silicon compound.

A pixel is defined by the opening pixel defined layer between the pixeldefined layers 223, and a single OLED is disposed for each pixel. Eachpixel may be a red pixel, a green pixel, a blue pixel, or a white pixelaccording to a color emitted by the organic emissive layer 220 of theOLED.

In some embodiments, the selective wavelength transparent layer 30 maybe provided to reduce reflection by external light while maintaininglight efficiency that may be increased by the inclined structure 209.

In some embodiments, the selective wavelength transparent layer 30 maybe provided on the first electrode 221 disposed on the side wall of theinclined structure 209. In some embodiments, the selective wavelengthtransparent layer 30 may transmit only light of a wavelength rangegenerated in the organic emissive layer 220 of each pixel and may nottransmit light of other wavelength ranges. In other words, a selectivewavelength transparent layer 30 that transmits only a red light isprovided in a red pixel, a selective wavelength transparent layer 30that transmits only a green light is provided in a green pixel, and aselective wavelength transparent layer 30 that transmits only a bluelight is provided in a blue pixel.

Thus, the light generated in the organic emissive layer 220 of eachpixel and traveling to a side surface thereof may transmit through theselective wavelength transparent layer 30 disposed on a inclined surfaceand then may be reflected from the first electrode 221 and emitted tothe outside, whereas most of the light incident from the outside may nottransmit through the selective wavelength transparent layer 30 and maybecome extinct.

For example, the selective wavelength transparent layer 30 thattransmits only the red light is provided in the red pixel so that thered light generated in the organic emissive layer 220 may transmitthrough the selective wavelength transparent layer 30. Then the lightmay be reflected from the first electrode 221 disposed on the inclinedsurface and be emitted to the outside, whereas visible light of thelight incident from the outside, except for the red light, may nottransmit through the selective wavelength transparent layer 30 and thusmay not be reflected from the first electrode 221.

In some embodiments, the selective wavelength transparent layer 30 maybe a red, green, or blue color filter according to each pixel. In someembodiments, the selective wavelength transparent layer 30 may have astructure in which low refractive index layers and high refractive indexlayers are alternately stacked, as described with reference to FIGS. 4and 5 below.

FIGS. 4 and 5 are schematic cross-sectional views of the selectivewavelength transparent layer 30 applied to embodiments of the presentinvention.

Referring to FIG. 4, an N(N°3, N is an integer) number of low refractiveindex layers 1 a, 2 a, 3 a, . . . , Na and an N number of highrefractive index layers 1 b, 2 b, 3 b, . . . , Nb may be alternatelystacked in the selective wavelength transparent layer 30. Although thelow refractive index layer 1 a is disposed as a lowermost layer of theselective wavelength transparent layer 30, the present embodiments arenot limited thereto, and the high refractive index layer 1 b may bedisposed as a lowermost layer of the selective wavelength transparentlayer 30.

A difference in a refractive index n between the low refractive indexlayers 1 a, 2 a, 3 a, . . . , Na and the high refractive index layers 1b, 2 b, 3 b, . . . , Nb may be equal to or greater than approximately0.5. A thickness d1 of each of the low refractive index layers 1 a, 2 a,3 a, . . . , Na and a thickness d2 of each of the high refractive indexlayers 1 b, 2 b, 3 b, . . . , Nb may be designed such that a light path(nd, n denotes the refractive index, and d denotes a moving distance oflight) is λ/4. In this regard, λ may denote a wavelength of light thatmay transmit through the selective wavelength transparent layer 30.

In this regard, a thickness d3 of at least one of the low refractiveindex layers 1 a, 2 a, 3 a, . . . , Na may be different from thethickness d1 of the other layers. For example, the thickness d3 of atleast one of the low refractive index layers 1 a, 2 a, 3 a, . . . , Namay be greater than the thickness d1 of the other layers. In someembodiments, the low refractive index layer having a different thicknessmay be disposed in the middle of the selective wavelength transparentlayer 30.

FIG. 5 shows the selective wavelength transparent layer 30 in a casewhere the low refractive index layers 1 a˜6 a and the high refractiveindex layers 1 b˜6 b are 6 pairs.

Referring to FIG. 5, the selective wavelength transparent layer 30 has astructure in which the low refractive index layer 1 a, the highrefractive index layer 1 b, the low refractive index layer 2 a, the highrefractive index layer 2 b, . . . , the low refractive index layer 6 a,and the high refractive index layer 6 b are stacked.

In some embodiments, the first through sixth low refractive index layers1 a˜6 a may have a same or similar refractive index. The first throughsixth high refractive index layers 1 b˜6 b may have a same or similarrefractive index.

In some embodiments, the refractive index of each of the first throughsixth low refractive index layers 1 a˜6 a may be approximately 0.5 timesor more smaller than that of each of the first through sixth highrefractive index layers 1 b˜6 b.

In some embodiments, the thickness d1 of the first, second, third,fifth, and sixth low refractive index layers 1 a, 2 a, 3 a, 5 a, and 6 amay be the same or similar. In some embodiments, the thickness d2 of thefirst through sixth high refractive index layers 1 b˜6 b may be the sameor similar. In some embodiments, the thickness d1 may be smaller thanthe thickness d2.

In some embodiments, the fourth low refractive index layer 4 a may havea thickness d3 that is different from those of the first, second, third,fifth, and sixth low refractive index layers 1 a, 2 a, 3 a, 5 a, and 6a. In some embodiments, the thickness d3 of the fourth low refractiveindex layer 4 a may be 1.5 times or more greater than the thickness d1of the first, second, third, fifth, and sixth low refractive indexlayers 1 a, 2 a, 3 a, 5 a, and 6 a.

FIGS. 6A through 6C are graphs showing a characteristic of the selectivewavelength transparent layer 30 of FIG. 5 according to a design changethereof.

Common design parameters with respect to data of FIGS. 6A through 6C areas follows:

1) Refractive index of the low refractive index layers 1 a˜6 a: 1.5

2) Refractive index of the high refractive index layers 1 b˜6 b: 2.3

3) Thickness d1 of the first, second, third, fifth, and sixth lowrefractive index layers 1 a, 2 a, 3 a, 5 a, and 6 a: 70 nm

4) Thickness d2 of the high refractive index layers 1 b˜6 b: 100 nm

The data of FIGS. 6A through 6C shows the characteristic of theselective wavelength transparent layer 30 with respect to a change inthe thickness d3 of the fourth low refractive index layer 4 a.

Referring to FIG. 6A, the thickness d3 of the fourth low refractiveindex layer 4 a is 140 nm. In this case, light of a wavelength fromabout 460 nm to about 470 nm in a visible light range may be transmittedlike a region A, which represents a blue light.

Referring to FIG. 6B, the thickness d3 of the fourth low refractiveindex layer 4 a is 220 nm. In this case, light of a wavelength fromabout 520 nm to about 530 nm in a visible light range may be transmittedlike a region B, which represents a green light.

Referring to FIG. 6C, the thickness d3 of the fourth low refractiveindex layer 4 a is 320 nm. In this case, light of a wavelength fromabout 610 nm to about 620 nm in a visible light range may be transmittedlike a region C, which represents a red light.

As described above, the design change of the selective wavelengthtransparent layer 30 may be made by changing a thickness of one of aplurality of low refractive index layers so as to transmit light of adesired wavelength range.

The above-described design parameter is merely an example, and may bechanged in various ways. For example, a difference in a refractiveindex, the number of low refractive index layers having differentthicknesses, a location of a low refractive index layer having adifferent thickness, etc. may be changed. Also, the selective wavelengthtransparent layer 30 may be designed by changing a thickness of at leastone of high refractive index layer instead of low refractive indexlayers.

FIG. 7 is a schematic cross-sectional view of region I of FIGS. 1 and 2,according to another embodiment of the present invention. The samereference numerals between FIGS. 3 and 7 denote the same elements, andthus repeated descriptions thereof are omitted here for brevity ofexplanation.

Referring to FIG. 7, an organic light-emitting display apparatus 200 isdifferent from the organic light-emitting display apparatus 100 of FIG.3 in that the organic light-emitting display apparatus 200 does notinclude the selective wavelength transparent layer 30 and insteadincludes a pixel defined layer 225 functioning as the selectivewavelength transparent layer 30.

In some embodiments, the pixel defined layer 225 may be a color filter.That is, the pixel defined layer 225 may transmit only light of awavelength range generated in the organic emissive layer 220 of eachpixel and may not transmit light of other wavelength ranges. In otherwords, a pixel defined layer 225 that transmits only a red light isprovided in a red pixel, a pixel defined layer 225 that transmits only agreen light is provided in a green pixel, and a pixel defined layer 225that transmits only a blue light is provided in a blue pixel.

Thus, the light generated in the organic emissive layer 220 of eachpixel and traveling to a side surface may transmit through the pixeldefined layer 225 and then may be reflected from the first electrode 221and emitted to the outside, whereas most of the light incident from theoutside may not transmit through the pixel defined layer 225 and maybecome extinct.

FIG. 8 is a schematic cross-sectional view of a region I of FIGS. 1 and2, according to another embodiment of the present invention. The samereference numerals between FIGS. 3 and 8 denote the same elements, andthus repeated descriptions thereof are omitted here for brevity ofexplanation.

Referring to FIG. 8, an organic light-emitting display apparatus 300 isdifferent from the organic light-emitting display apparatus 100 of FIG.3 in that the organic light-emitting display apparatus 300 has a topemissive structure in which light is emitted in a direction of thesubstrate 21.

In some embodiments, the organic light-emitting display apparatus 300may include an insulating layer 210 having a inclined structure 209having a protruding shape. Also, an OLED may be provided on a protrudingportion of the insulating layer 210. In this case, the first electrode221 may be a transparent electrode and have a convex shape. In someembodiments, the second electrode 222 may include a reflective material.

In some embodiments, the selective wavelength transparent layer 30 maybe disposed on the first electrode 221 disposed on the sidewall of theinclined structure 209. In some embodiments, the selective wavelengthtransparent layer 30 may transmit only light of a wavelength rangegenerated in the organic emissive layer 220 of each pixel and may nottransmit light of other wavelength ranges.

Thus, the light generated in the organic emissive layer 220 of eachpixel and traveling in a direction of a side surface thereof may bereflected from the second electrode 222 and then emitted toward thesubstrate 21, whereas most of the light incident from the outside maynot transmit through the selective wavelength transparent layer 30 andmay become extinct, and thus an external light reflectivity of theorganic light-emitting display apparatus 300 may be reduced.

It should be understood that example embodiments described herein shouldbe considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments. While some example embodiments havebeen particularly shown and described, it will be understood by one ofordinary skill in the art that variations in form and detail may be madetherein without departing from the spirit and scope of the claims.

What is claimed is:
 1. An organic light-emitting display apparatuscomprising: an insulating layer having a inclined structure; a firstelectrode disposed on the insulating layer; a selective wavelengthtransparent layer disposed on the first electrode; a pixel defined layerdisposed on the insulating layer and the first electrode and defining anemissive region and a non-emissive region; an organic emissive layerdisposed on the first electrode; and a second electrode disposed on theorganic emissive layer.
 2. The organic light-emitting display apparatusof claim 1, wherein the first electrode is provided on a bottom surfaceand a sidewall of the inclined structure.
 3. The organic light-emittingdisplay apparatus of claim 1, wherein the pixel defined layer extends onan upper surface of the insulating layer, and the emissive regioncomprises an opening exposing the first electrode.
 4. The organiclight-emitting display apparatus of claim 1, wherein the pixel definedlayer covers the selective wavelength transparent layer.
 5. The organiclight-emitting display apparatus of claim 1, wherein the selectivewavelength transparent layer further comprises an N(N≧3, N is aninteger) number of low refractive index layers alternately stacked withan N number of high refractive index layers, wherein one of the lowrefractive index layers has a thickness T¹ and each of the other lowrefractive index layers has a thickness T².
 6. The organiclight-emitting display apparatus of claim 5, wherein a difference in arefractive index between the N number of low refractive index layers andthe N number of high refractive index layers is equal to or greater than0.5.
 7. The organic light-emitting display apparatus of claim 5, whereinthe thickness T¹ is greater than the thicknesses T².
 8. The organiclight-emitting display apparatus of claim 5, wherein a thickness of anintermediate layer of the low refractive index layers is greater thanthicknesses of the other low refractive index layers.
 9. The organiclight-emitting display apparatus of claim 1, wherein a sidewall of theinclined structure has a tilt angle in a range from about 20 degrees toabout 70 degrees with respect to an extending line of a bottom surfaceof the inclined structure.
 10. The organic light-emitting displayapparatus of claim 1, wherein the inclined structure has a recess shape,and the first electrode has a concave shape.
 11. The organiclight-emitting display apparatus of claim 1, wherein the first electrodeis disposed on a sidewall of the inclined structure, and reflects lightgenerated in the organic emissive layer.
 12. The organic light-emittingdisplay apparatus of claim 1, wherein the inclined structure has aprotruding shape, and the first electrode has a convex shape.
 13. Theorganic light-emitting display apparatus of claim 1, wherein the firstelectrode is a transparent electrode, and the second electrode is abottom emissive type comprising a reflective layer.
 14. An organiclight-emitting display apparatus comprising: a substrate; an insulatinglayer disposed on the substrate and comprising a recess having ainclined surface; an organic light-emitting diode (OLED) disposed on theinsulating layer and comprising a first electrode, an organic emissivelayer, and a second electrode; a pixel defined layer disposed betweenthe first electrode and the second electrode and defining an emissiveregion and a non-emissive region; and a selective wavelength transparentlayer provided on the inclined surface.
 15. The organic light-emittingdisplay apparatus of claim 14, wherein the first electrode is disposedon the inclined surface.
 16. The organic light-emitting displayapparatus of claim 14, wherein the insulating layer further comprises aplurality of recesses, and the OLED is disposed in each of the recesses.17. The organic light-emitting display apparatus of claim 14, wherein anN(N≧3, N is an integer) number of low refractive index layers and an Nnumber of high refractive index layers are alternately stacked in theselective wavelength transparent layer, wherein one of the lowrefractive index layers has a thickness T³ and each of the other lowrefractive index layers has a thickness T⁴, and wherein thickness T³ isdifferent than the thicknesses T⁴.
 18. The organic light-emittingdisplay apparatus of claim 14, further comprising: a thin filmtransistor connected to the first electrode.
 19. The organiclight-emitting display apparatus of claim 14, further comprising asealing film covering the OLED.
 20. The organic light-emitting displayapparatus of claim 14, wherein the first electrode comprises areflective layer.
 21. An organic light-emitting display apparatuscomprising: a substrate; an insulating layer disposed on the substrateand comprising a plurality of recesses each having a inclined surface; aplurality of OLEDs disposed on the insulating layer and comprising afirst electrode, an organic emissive layer, and a second electrode; anda pixel defined layer disposed between the first electrode and thesecond electrode and defining an emissive region and a non-emissiveregion, wherein the pixel defined layer is a color filter.
 22. Theorganic light-emitting display apparatus of claim 21, wherein theinclined surface has a tilt angle in a range from about 20 degrees toabout 70 degrees with respect to a parallel line of the substrate. 23.The organic light-emitting display apparatus of claim 21, wherein thefirst electrode is disposed on the inclined surface.